Tropical Inundation Does Not Explain 2020-2022 Methane Surge

Atmospheric methane is rapidly increasing, and the role of tropical wetlands in the global methane budget 12 raises concerns about a potential climate-wetland-methane feedback. Here we use Cyclone Global 13 Navigation Satellite System observations to map monthly inundation dynamics across the tropics (37.4 ºS 14 to 37.4 ºN) at high resolution (0.01º × 0.01º) over five years (2018–2023), including cloud and vegetation15 covered regions. Our results reveal large seasonal and interannual variations in wetland extent not captured 16 in traditional inundation products, with strong El Niño-Southern Oscillation correlations. Tropical wetland 17 models driven by these inundation observations, independent precipitation products, or constrained by total 18 water observations do not show growth in wetland methane emissions from 2020-2022. This suggests the 19 2020-2022 growth in methane is best explained by other methane source or sink mechanisms, or that non20 hydrological controls are more important in tropical wetland methane emissions than currently understood.